In the first comprehensive assessment on “invasive alien species”, a biodiversity organization warned that plants and animals which have been forced to leave their natural habitats by human activity can have a devastating impact on global economy and environment.
The Intergovernmental Science-Policy Platform on Biodiversity and Ecosystem Services, or Ipbes, estimated that the annual economic costs of damage to nature, harm to human health and economic activity such as farming and fisheries, were $423bn. It warned policymakers they are not taking adequate action to combat the increasing threat of alien species.
The report was prepared over four years by 86 scientists. It found that humans had moved 37,000 animal, plant and microbe species to new habitats all around the globe. The extent of their damage led to the classification of more than 3,500 species as invasive aliens.
Scientists at Ipbes said that the $423 billion economic impact of invasive species calculated for 2019 was a “very modest” estimate, and costs are quadrupling each decade. The 143 member countries of the organization meeting in Bonn on this weekend approved their report.
Anibal Pauchard, co-author and professor at Concepcion University in Chile, stated that invasive alien species were a major cause of 60 percent of animal and plant extinctions worldwide and were the sole factor for 16 percent of these events.
He said that it would be a costly mistake to think of biological invasions as someone else’s issue. These “risks” have global roots, but local impacts for people in all countries. Ipbes stated that even Antarctica was affected by the seeds accidentally introduced by tourists and scientists.
Ipbes said that to stop the tide, it was necessary to take preventive action on a national and global level, by enhancing biosecurity, and detecting and eradicating newly introduced species, before they became permanently established. Water hyacinth is the most common invasive species. It is native to South America, and is one of nature’s fastest growing plants. This plant clogs lakes and rivers all over the world, with devastating effects on freshwater fisheries, especially in Africa.
The second most common alien species on the Ipbes’ list is lantana. This flowering shrub originally from Central and South America was planted as an ornamental in gardens, but is now viewed as an invasive weed which is interfering more with agriculture. The black rat is third, having decimated native birds and fauna on islands around the world after it escaped from ships.
Helen Roy, co-author of the UK Centre for Ecology and Hydrology and a UK Centre for Ecology and Hydrology expert, said: “We are seeing unprecedented rates of growth with 200 alien species being recorded every year.”
The introduction of a new species as a means to eliminate a pest can reduce damage. However, this strategy has often backfired in a disastrous way. The harlequin Ladybird is a good example. This Asian native was brought to the US to control insects pests in the early twentieth century. However, it has now become a destructive predator to native species.
Roy explained that the approach might work if it is introduced after a rigorous risk assessment. The alien jacaranda insect was decimating native gumwood trees on the isolated Atlantic island of St Helena until a ladybird was introduced. She said, “It’s really specific for controlling the bug.” “That little ladybird saved the gumwoods.”
Peter Stoett, University of Ontario Institute of Technology’s third co-chair of Ipbes, stated that ambitious progress could be made in the fight against invasive alien species.
He said that a context-specific, integrated approach is required to provide biosecurity across and within nations and in the different sectors. This will benefit both nature and humans.